With the requirement on the bandwidth of a bearer network becoming higher and higher, a beyond-100 G technology becomes a solution to meeting the requirement for higher bandwidth; the Wavelength Division Multiplexing (WDM) of the conventional 50 GHz fixed grid cannot provide a sufficient spectrum width to realize a beyond-100 G technology, no matter a 400 G technology or a 1 T technology.
In view of the defects of the fixed grid, a flexible grid capable of providing wider bandwidth is needed. In related technologies, beyond-100 G multi-rate hybrid transmission and the flexibility of the modulation format for beyond-100 G transmission have different requirements on channel bandwidth. If a proper bandwidth is customized for each channel, then the bandwidth of a system can be fully used, thereby generating a flexible grid system.
The requirement for an ultra high-speed WDM system brought by the demand for higher and higher bandwidth leads to a demand for a flexible grid technology. Moreover, the transmission rate of single-carrier is close to the limit of optical transmission capacity, the transmission capacity of optical fiber can be improved by using multi-carrier, however, how to effectively plan and manage frequency spectrum and how to realize the compatibility to existing systems remain to be solved.
As to the problem of how to effectively plan and manage frequency spectrum for an introduced flexible grid technology existing in related technologies, no effective solution have been proposed.